Over the past few days, hurricane Irene has grown as it approaches the United States. The NASA/NOAA Earth-observing GOES 13 satellite has been keeping an eye on the storm, and images it has taken have been put together into this dramatic video showing Irene from August 23 at 10:40 UTC to 48 hours later… just a few hours ago as I write this:
Pay attention about 20 seconds into the video (August 23 at about 20:00 according to the clock at the top of the video). You can see the eye wall region burst into existence, and a few seconds later the eye itself suddenly appears. Also, a surge of white clouds appears to the right of the eye and wraps around the hurricane. That’s where warm air has risen strongly, overshooting the cloud tops, and producing intense rainfall (5 cm/hour according to TRMM!). Overshooting tops, as they’re called, happen frequently in tropical storms as they intensify. For what it’s worth, something like that happens in stars as well as hot plasma rises rapidly from under the surface, though astronomers tend to call it "convective overshoot".
Irene is currently a strong Category 3 hurricane (with sustained winds at 200 kph (120 mph)), and is expected to start affecting the east coast today. If you live along the coast, take precautions, and please, stay safe.
Video credit: NASA/NOAA GOES Project
Holy Hurricanes. NASA’s Terra Earth-observing satellite caught this incredible and beautiful image of two major hurricanes in the western Atlantic ocean:
[Click to encategory5ennate.]
The northern one is Danielle, the southern Earl. This image, taken on the morning of August 29 (just a few hours ago as I write this) shows them off the US east coast. The image has the Leeward Islands — north of Venezuela and east of Puerto Rico — outlined on the western side of Earl. It’s not likely that either will have their eyes move over land, but they hardly need to for there to be an impact. Earl is Category 4 as it is now (150 mph sustained winds) but that’s near the eye; the edges will almost certainly sweep over the coast of North Carolina which still means lots of wind and rain. Most likely the coast will be spared a full onslaught, but if you live there, it’s best to be prepared for stormy weather.
Danielle is weaker and likely to wane more as it moves north; the waters are colder, starving it of the heat needed to sustain its shape and coherence. Incredibly, though, it’s 1000 km (600 miles) across. Still, it’s unlikely to have much of an impact on the US.
Chris Mooney at Discover’s The Intersection blog is keeping a close eye on these, as well as on Fiona, which is starting to gain strength in the Atlantic as well. Chris wrote the fascinating book Storm World, which is about hurricanes, so it’s no surprise he’s on top of this. You can also read NASA’s Terra page about this image to learn more.